Book Image

Get Your Hands Dirty on Clean Architecture - Second Edition

By : Tom Hombergs
4 (1)
Book Image

Get Your Hands Dirty on Clean Architecture - Second Edition

4 (1)
By: Tom Hombergs

Overview of this book

Building for maintainability is key to keep development costs low (and developers happy). The second edition of "Get Your Hands Dirty on Clean Architecture" is here to equip you with the essential skills and knowledge to build maintainable software. Building upon the success of the first edition, this comprehensive guide explores the drawbacks of conventional layered architecture and highlights the advantages of domain-centric styles such as Robert C. Martin's Clean Architecture and Alistair Cockburn's Hexagonal Architecture. Then, the book dives into hands-on chapters that show you how to manifest a Hexagonal Architecture in actual code. You'll learn in detail about different mapping strategies between the layers of a Hexagonal Architecture and see how to assemble the architecture elements into an application. The later chapters demonstrate how to enforce architecture boundaries, what shortcuts produce what types of technical debt, and how, sometimes, it is a good idea to willingly take on those debts. By the end of this second edition, you'll be armed with a deep understanding of the Hexagonal Architecture style and be ready to create maintainable web applications that save money and time. Whether you're a seasoned developer or a newcomer to the field, "Get Your Hands Dirty on Clean Architecture" will empower you to take your software architecture skills to new heights and build applications that stand the test of time.
Table of Contents (18 chapters)

Post-compile fitness function

As soon as we use the public modifier on a class, the compiler will let any other class use it, even if the direction of the dependency points in the wrong direction according to our architecture.

Since the compiler won’t help us out in these cases, we have to find other means to check that the Dependency Rule isn’t violated.

One way is to introduce a fitness function – a function that takes our architecture as input and determines its fitness in regard to a specific aspect. In our case, fitness is defined as the Dependency Rule is not violated.

Ideally, a compiler runs a fitness function for us during compilation, but, lacking that, we can run such a function at runtime, after the code has already been compiled. Such runtime checks are best run during automated tests within a continuous integration build.

A tool that supports this kind of architectural fitness function for Java is ArchUnit.1 Among other things, ArchUnit...